Field of the Invention
The invention relates to a hydraulic punch machine, as well as a punch carrier for a punch machine, comprising:                a piston unit exchangeably arranged on the punch machine, and        a punch holder arranged on the piston unit for exchangeably arranging a punch.        
Description of Related Art
Punch machines of the initially cited type are used to introduce holes into one or more pieces of sheet metal in a punching process which then serve to accommodate suitable connecting elements such as blind rivets, blind rivet screws and/or blind rivet nuts.
To produce the holes, the pieces of sheet metal are arranged in the punch machine between the punch as well as a die so that the hole can then be punched into the pieces of sheet metal, wherein the punch is adjusted in the direction of the die for this purpose. The size of the holes to be produced is determined according to the diameter of the punching section of the punches. In order to produce different holes, the punches are releasably arranged on a punch holder of a piston unit of the punch machine, wherein the piston unit can be moved in the direction of its longitudinal axis by a drive unit of the punch machine and thereby drives the punch through the pieces of sheet metal to be processed. At present, exchanging the punch is extremely time-consuming, especially since it must be ensured that all of the force acting on the punch in the punching process can be reliably transferred. A precise alignment of the punch is therefore particularly important in order to achieve correct punching results.